Rowley Shoals (17°20'S) and Scott Reef (14°03'S), WA, Ashmore Reef, Timor Sea (12°15'S) and Tijou Reef, QLD (13°05'S) to Seal Rocks, NSW (32°28'S) and Ashmore Reef, Coral Sea (10°24'S); tropical, east-Indo-west-central Pacific.
Timor Province (2), Cape Province (20), Cocos (Keeling) Island Province (22), Christmas Island Province (23), Northwest Transition (3), Central Eastern Shelf Province (38), Central Eastern Shelf Transition (39), Northeast Shelf Province (40), Northeast Shelf Transition (41)
Body short and deep, and strongly compressed. Preorbital bone convex and without strong spines. 1 prominent spines at angle of preopercle. Ventral edge of interopercle serrated. Eye moderately small. Mouth small, terminal, protractile, gape not extending to anterior rim or orbit. Dorsal fin with XV spines and 14 or 15 soft rays; anal fin with III spines and 17-18 soft rays; caudal fin rounded. Head and anterior half of trunk yellow with a blue blotch over the eye. Posterior half of trunk and tail blue. Caudal fin yellow.
Inhabits lagoon, channel, or protected seaward reef slopes, drop offs, coral and rubble areas at depths of 3 to 20 m. Usually in pairs or in small groups. Feeds on algae, small crustaceans and worms. Darts from one hiding place to the next.
Widely distributed in Indo-Pacific from East Africa to the Samoan and Phoenix Islands, north to southern Japan, south to New Caledonia; throughout Micronesia. It is found in eastern and southern Taiwanese waters.